Iruvar is a majestic and intelligent film telling the story of two powerful men who are instrumental in the politics of Tamil Nadu in the 1930s & 40s. Actor Anandan (Mohanlal), who dreams of becoming a star, meets political writer/poet Selvam (Prakash Raj). Anandan believes that together they can make cinema history while the poet puts greater store in making political history. Initially, their idealism and ambition draw them together but their friendship deteriorates when Anandan, now the big star, joins Selvam's party and clearly attracts a larger following than his mentor, Selvam.

South India has many popular stars who became politicians and, in some cases, Chief Ministers of their respective states. Although Iruvar is not based on any one particular star politician, its characters resemble star turned Chief Minister MG Ramachandra and his screenplay writing friend. The film is also the debut of former Miss World, Aishwarya Rai, in a dual role as Anandan's first wife and seductive co-star but Iruvar belongs to actors Mohanlal and Prakash Raj. Ratnam's usual team give the film its stunning visuals (cinematographer Santosh Sivan) and fantastic score (music director A.R Rahman).